1. Field of the Invention
This invention relates to a safety hook, more particularly to a safety hook provided with a safety lock unit.
2. Description of the Related Art
Referring to FIG. 1, U.S. Pat. No. 7,444,723 discloses a conventional safety hook 9 including: a hook body 91 defining a hook inner space 10 therein and a hook mouth 100 in spatial communication with the hook inner space 10; a latch unit 92 pivoted to the hook body 91 about a first axis (A) so as to be rotatable relative to the hook body 91 between locked and unlocked positions; a releasing unit 93 pivoted to the hook body 91 about a second axis (B) so as to be rotatable relative to the hook body 91; and a safety lock unit 94 disposed between the latch unit 92 and the releasing unit 93 and pivoted to the hook body 91 about a third axis (C) so as to be rotatable relative to the hook body 91 between restraining and releasing positions. The latch unit 92 blocks the hook mouth 100 when the latch unit 92 is disposed at the locked position, thereby denying access into the hook inner space 10 via the hook mouth 100.
The safety lock unit 94 has a pivoting middle portion 941 pivoted to the hook body 91, a restraining end portion 942 extending from one end of the pivoting middle portion 941 to abut against the latch unit 92, and a driven end portion 943 extending from the other end of the pivoting middle portion 941 to abut against the releasing unit 93 so as to permit the safety lock unit 94 to be driven by the releasing unit 93 to rotate from the restraining position to the releasing position. The restraining end portion 942 and the driven end portion 943 of the safety lock unit 94 form an angle of less than 180 degrees and greater than 90 degrees. The restraining end portion 942 of the safety lock unit 94 is perpendicular to the latch unit 92 when the safety lock unit 94 is disposed at the restraining position, thereby preventing rotation of the latch unit 92 from the locked position to the unlocked position. The restraining end portion 942 of the safety lock unit 94 is inclined to the latch unit 92 at an angle of less than 90 degrees when the safety lock unit 94 is disposed at the releasing position, thereby permitting rotation of the latch unit 92 from the locked position to the unlocked position.